1. Field of the Invention
The present invention relates to an ejector cycle with a defrosting operation of an evaporator.
2. Description of Related Art
In an ejector cycle described in JP-A-6-11197, refrigerant is decompressed and expanded in a nozzle of an ejector so that gas refrigerant evaporated in an evaporator is sucked, and pressure of refrigerant to be sucked into a compressor is increased by converting expansion energy to pressure energy. Further, in the ejector cycle, refrigerant flowing out of the ejector flows into a gas-liquid separator to be separated into gas refrigerant and liquid refrigerant in the gas-liquid separator. Then, the liquid refrigerant in the gas-liquid separator is supplied to the evaporator, and the gas refrigerant in the gas-liquid separator is supplied to the compressor.
Accordingly, the ejector cycle has a first refrigerant circulation where refrigerant circulates the gas-liquid separator→the evaporator→a pressure increasing portion of the ejector→the gas-liquid separator in this order, and a second refrigerant circulation where refrigerant circulates the compressor→a condenser→the ejector→the gas-liquid separator→the compressor in this order. Accordingly, in the ejector cycle, it is difficult to introduce high-temperature refrigerant to the evaporator in order to defrost the evaporator.
Generally, an expansion-valve refrigerant cycle has only one refrigerant flow where refrigerant circulates through a compressor→a condenser→an expansion valve→an evaporator→the compressor in this order. Therefore, in this expansion-valve refrigerant cycle, when the expansion valve is fully opened, high-temperature refrigerant flows into the evaporator, and defrosting operation of the evaporator can be readily performed.
In contrast, in the ejector cycle, the defrosting operation of the evaporator cannot be performed by using high-temperature refrigerant flowing from the condenser.